[Supras] Fuel pressure.

[Jeff Mohler]

Where is a URL of the 12v mod?

On 10/18/07, Rich Peacock <rdp at ix.netcom.com> wrote:
> There should be a check valve in the fuel pump to prevent back flow.
> Fuel pressure should drop very slowly after the key is off, but loosing
> all pressure overnight is totally normal.  Loosing pressure quickly
> might indicate a leaking injector or bad fuel pump check valve.  If you
> shut the motor off and it takes a bit to restart while still hot, that
> could be some form of fuel vapor lock.
>
> Easy test would be to place a jumper (paper clip) between B+ and Fp
> within the diag block.  This will send a 12v signal to the fuel pump
> when you turn the ignition on pre-priming the fuel system.  If that
> clears up your hard start problem, then you could check the voltage at
> the fuel pump (the Supra uses a resistor/relay to step between 9v and
> 12v to the fuel pump) or it might be time to replace the fuel pump.  If
> the car is still hard to start, you might want to look for a weak
> ignition.  Replacing the plugs and wires.
>
> Sean - once you do the 12v mod (putting 12v to the fuel pump via heavier
> gauge wire and relay when IGN is on), many Supras fire right up when you
> turn key.  Which actually might not be a bad idea for Vladimir's car
> either...
> -Rich
>
> Sean Cavanaugh wrote:
> > far as I know, that's normal. after car is off, fuel flows backwards thru
> > the pump into the tank. first few seconds of cranking reprimes the line with
> > fuel and you're good to go. I have never heard of a MKIII with a stock pump
> > that starts right up without a little lag.
> >
> > -Sean
> >
> > ----- Original Message -----
> > From: "Vladimir Ponomarev" <vladiborev at yahoo.com>
> > To: <supras at supras.com>
> > Sent: Thursday, October 18, 2007 6:07 PM
> > Subject: [Supras] Fuel pressure.
> >
> >
> >> Hi guys. I have noticed a fuel pressure drop after my 91T with 170 kmiles
> >> sits overnight in the garage or even after few hours after stop. It takes
> >> time to build fuel pressure again and to crank her. Question: what is the
> >> most likely cause of the pressure drop? I have switched to AFPR, but it
> >> didn't help. What is my next bet?
> >> Thanks.
> >>
> >> Vlad.
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> >
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